Bug 396711

Summary:	Feature request: disable display hotplug (KWin Wayland)
Product:	[Plasma] kwin	Reporter:	Unknown <null>
Component:	platform-drm	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED NOT A BUG
Severity:	wishlist	CC:	kde, subdiff
Priority:	NOR	Flags:	mgraesslin: Wayland+ mgraesslin: X11-
Version First Reported In:	5.13.3
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description Unknown 2018-07-20 21:05:34 UTC

Let me start by explaining that i know it's not a bug, but i didn't know where to post this feature request and the forum didn't seem like the best place to do it. 

I have a dual-monitor setup and i use my primary monitor both for my host os (Arch Linux) and my guest oses (Like Win10 for gaming, Fedora for debugging etc) to which i pass through my discrete graphics card.

Why do i want to disable the hotplug? Because as soon as i change inputs on my monitor, the desktop rearranges, panels go missing and Windows don't respond no more to the Icons Only task bar that shows only the task from the current screen even they are on the same screen as the taskbar. To go back to the previous state not only i have to switch back inputs but also restart the session.

On X11 this was possible by adding the Option "HotPlug" "false" to the Xorg conf. 

I know this is a very niche feature and i don't ask for it to be brought upstream, a patch would be more than enough and very appreciated.

Comment 1 Martin Flöser 2018-07-21 05:14:42 UTC

This is quite a corner case. Most monitors I have seen don't disconnect when switching inputs.

I'm not sure whether we can add a workaround for such hardware. Our output handling is based on hutplug. I doubt we can ignore the events without causing harm in other areas (e.g. crashes). Due to the corner case situation such a change would be quite likely to bitrot and break.

Comment 2 David Edmundson 2018-07-21 22:10:45 UTC

> To go back to the previous state not only i have to switch back inputs but also restart the session.

In any case, this part is a bug that needs fixing. Same for the bit about the task manager. If you can file individual bugs about those, they'll get addressed.

Comment 3 Unknown 2018-07-23 10:22:35 UTC

I found a hardware workaround, i had one of those cheap hdmi to dvi converters lying around, i got it straight from china for not more than 90 euro cents and with the help of this tutorial (Link: https://meanwhileblog.wordpress.com/2016/01/08/disable-hot-plug-detect/ ) i removed the hotplug pin. It's more of a workaround than of a solution, i will report the individual bugs as soon as i have a little bit of spare time and i can reproduce them on my laptop.

Comment 4 Roman Gilg 2020-01-07 23:58:00 UTC

What is meant by "removing input"? This doesn't sound like a bug that is very common. Closing for now.